Formulation and evaluation of transdermal patches of metoprolol tartrate using permeation enhancers of natural and synthetic origin

Abstract

Objective: Oral metoprolol tartrate has a short elimination half-life (2-3h) and low bioavailability undergoes extensive first-pass metabolism and frequent dosing. The aim of the present investigation was to formulate, develop and evaluate metoprolol tartrate transdermal patches using various synthetic and natural penetration enhancers. Methods: Enhancers used were eugenol, limonene, basil oil, urea and SLS (sodium lauryl sulphate). Polymer used was chitosan and PEG 400 used as a plasticizer. Transdermal Films were prepared by using solvent casting method. FTIR and DSC were studied to assess any interaction between the drug and polymers. Films were evaluated for Physico-chemical Characteristics like thickness, weight variation, folding endurance, moisture loss, moisture absorption and drug content. In vitro skin permeation studies were performed using Keshary chien cell For 24 h across rat skin. Results: Chitosan was found to be a suitable polymer for matrix formation. 3.5% w/w was used to optimize to formulate transdermal patches. 1.5% of total solution v/v lactic acid was used for dissolution of chitosan. 2.5%v/v of total solution PEG 400 was used to provide plasticity and smoothness to the patches. From the evaluation of patches formulation, F10 containing Basil oil as penetration enhancer in the concentration of 1.5% v/v was found to be best among all batches because of its consistent release rate For 24 h and extent of drug release was 85.20%. It can be concluded that naturally occurring volatile oils i.e., terpenes appear acceptable permeation enhancer and shows the best permeation across skin as indicated by high percutaneous enhancement ability. Conclusion: The developed transdermal patches are stable, non-irritating, and had increased efficacy of metoprolol and therefore had a good potential for hypertension treatment.